This section provides background information related to the present disclosure which is not necessarily prior art.
Compressors are used in a wide variety of industrial and residential applications to circulate refrigerant within a refrigeration, heat pump, HVAC, or chiller system (generically referred to as “refrigeration systems”) to provide a desired heating and/or cooling effect. In any of the foregoing systems, the compressor should provide consistent and efficient operation to ensure that the particular refrigeration system functions properly.
Compressor systems may include multiple compressors connected together for increased efficiency and capacity modulation. The compressors have the capability to operate together or individually, delivering different capacity steps as needed. System capacity can be modulated by using multiple refrigeration circuits or by using multiple compressors in a single-circuit. For example, in a four compressor system, frequently used in packaged rooftops, individual compressors can be turned on and off or be set to different capacity levels to achieve different outputs.
Typically thermostat based controllers stage the compressor based on a sensible demand which is determined based on the thermostat set temperature and process value. There are other control systems which are based on outdoor air temperatures (OAT). In this case the OAT set temperature and process value together determine the sensible demand. Instead of OAT or Indoor thermostat, some other measurable parameter such as return air temperature (RAT) or supply air temperature (SAT) could also be used to determine the demand.
However, the disclosure herein addresses a new system and method for predicting the load either using an OAT sensor locally or more significantly, using the OAT data from reliable web portals/services such that a sensor could potentially be eliminated and the demand is calculated through a mathematical model.